Power operated wrench mechanism

ABSTRACT

A motor operated wrench mechanism for imparting successive rotative movement to an object to which the wrench mechanism is applied. The wrench mechanism includes a motor which imparts reciprocational movement to a connecting rod through a worm gear eccentric crank shaft mechanism. The connecting rod imparts successive rotational movements to a ratchet gear through a driving mechanism including a plurality of driving pawls capable of varying the effective rotative driving stroke of the drive mechanism. A lost motion connection may be provided between the connecting rod and the ratchet drive mechanism to provide infinite variance in the length of the operative stroke of the wrench mechanism and to provide impacting actuation of the drive mechanism for breaking loose the object to be rotated.

United States. Patent 1191 Bartusch Feb. 12, 1974 POWER OPERATED WRENCH1,871,857 8/1932 Martois 81/5739 x MECHANISM 2,711,110 6/1955 Brame81/58.]

[76] Inventor: Alexander P. Bartusch, 40333 i Central Ave coldspringsiTex Prrmary Examiner-James L. Jones, Jr. 92343 [57] ABSTRACT [22] Filed:Mar. 20, 1969 A motor operated wrench mechanism for imparting PP 808,774successive rotative movement to an object to which Related U.S.Application Data Continuation-in-part of Ser. No. 669,668, Sept. 21,1967, abandoned References Cited UNITED STATES PATENTS 5/1956 Schneider74/l42 X 6/193] Weaver..... 81/5739 6/1966 Medesha... .s1/57.13 12/1955Blackburn ..s1/57.39x

the wrench mechanism is applied. The wrench mechanism includes a motorwhich imparts reciprocational movement to a connecting rod through aworm gear eccentric crank shaft mechanism. The connecting rod impartssuccessive rotational movements to a ratchet gear through a drivingmechanism including a plurality of driving pawls capable of varying theeffective rotative driving stroke of the drive mechanism. A lost motionconnection may be provided between the connecting rod and the ratchetdrive mechanism to provide infinite variance in the length of theoperative stroke of the wrench mechanism and to provide impactingactuation of the drive mechanism for breaking loose the object to berotated.

5 Claims, 8 Drawing Figures PATENTEUFEB 12 I974 SHEET 1 [1F 2 AlexanderF. Bartusch /N VE N TOR A TTORNE Y iATENTED FEB l 2 I974 SHEET 2 (IF 2FIGS Alexander P. Bartusch IN VE N TOR A TTORNE Y 1. POWER OPERATEDWRENCH MECHANISM This is a continuation-in-part of applicants priorpatent application serial number 669,668 filed September 21, 1967, nowabandoned.

BACKGROUND OFTHE INVENTION This invention relates generally to a motoroperated wrench mechanism which is capable of imparting rotationalmovement to an object to be rotated such as a hand wheel of a valve, abolt to be tightened or loosened, or the like. This invention will bedescribed particularly as it relates to the rotation of a valve handwheel, but such specific use is not intended to limit the spirit orscope of this invention. This application will also be directedparticularly to utilization of the invention in a portable valveactuating mechansim, but it is intended that this invention be capableof utilization in stationary valve operator mechanisms within the sprirtand scope of this invention.

Valves which are located in various processing or refining plants or arelocated on ocean going tanker vessels and the like are frequentlypositioned so that operation thereof is made difficult, especially ifthe valve requires extremely high breakloose or opening torque. It istherefore frequently found necessary to provide motor energized valveactuators for such valves because of the difficulty of opening andclosing the same. Provision of motor energized valve actuators isgener-. ally an expensive proposition which could increase cost to animpractical degree. I

It is therefore a primary object of my invention to provide an improvedmotor operated wrench mechanism which may be portable in constructionallowing utilization of a'limited number of wrench mechanisms foropening and closing valves.

It is another object of this invention to provide a novel motor operatedwrench mechanism which is capable of being powered by various acceptablepower means, such as electric or pneumatically actuated motors orinternal combustions engines and the like.

Among the several objects of my invention is contemplated the provisionof a novel motor operated wrench mechanism having the ability to rotatean object either clockwise or counterclockwise and also having theability to loosen screwed parts which are substantially frozen in place.

the structures hereinafter described and the scope of which will beindicated in the appended claims.

In the accompanying drawings, in which two of various possibleembodiments of the invention are illustrated;

FIG. 1 is a plan view of the invention having portions thereof brokenaway and illustrated in section.

FIG. 2 is a side view of the motor operated wrench mechansirn of FIG. 1,having a portion thereof broken away and illustrating the ratchet geardrive mechanism therof in detail.

FIG. 3 is a sectional view of the motor operated wrench mechanism ofthis invention taken along the line 3-3 in FIG. 1 and illustratingutilization of the wrench mechanism with a hand wheel adapter to operatethe hand wheel'of a valve.

FIG. 4 is a fragmentary sectional view in plan illustrating a modifiedembodiment of this invention.

FIG. 5 is an elevation view illustrating a hand wheel adapter tool whichis utilized with the motor operated wrench mechansim for opening andclosing gate valves.

FIG. 6 is a fragmentary plan view illustrating a portion of a valve handwheel in phantom and showing association of the ball spring catchstructures of a hand wheel adapter tool to the valve hand wheel.

FIG. 7 is a sectional view taken along line 7--7 in FIG. 8 andillustrating a modified valve hand wheel adapter tool for utilizationwith the motor operated wrench mechanism.

FIG. 8 is a plan view of the hand wheel adapter tool of FIG. 7.

Briefly this invention concerns a motor operated wrench mechanism whichutilizes a rotary motor such as an electric motor, pneumatic motor, orthe like, which is disposed in driving connection with a worm gearcapable of inducing rotation to an eccentric member. The motor driveneccentric imparts reciprocation to a connecting rod mechanism which inturn imparts successive rotational movements to a ratchet gear drivemechanism. The ratchet gear drive mechanism includes a plurality ofdriving pawls which may be of It is an even further object of thisinvention to provide a novel motor operated wrench mechanism which isprovided in the form of a totally enclosed unit which is lubricated forlife and is able to function efiiciently with various adapter tools suchas nut and bolt sockets, valve hand wheel adapters, and the like.

It is another important object of my invention to pro vide a novel motoroperated wrench mechanism which is portable and is of such size, design,and weight that it may be utilized effectively in restricted areas suchas for the operation of valves located in small pits or in the holds ofships and the like.

Another object of my invention involves the provision of a novel motoroperated wrench mechanism which is simple in nature, reliable in use,and low in cost.

The invention accordingly comprises the elements and combination ofelements, features of construction and arrangement of parts which willbe exemplified and operatively associated therwith. A stopping pawl isprovided to prevent retrograde rotation of the ratchet gear and mayinclude a plurality of steps thereon for limiting partial toothretrograde rotation upon operation of the partial tooth driving pawls aswill be described herein below. The ratchet gear includes internalsplines which are adapted to mate with the external driving splines of avalve hand wheel adapter tool or the like. The internal splinedconnection of the motor operated wrench mechanism is accessible fromeither side thereof to achieve clockwise or counterclockwise rotation ofthe valve hand wheel without the necessity of providing an internalreversing mechanism. The motor operated wrench mechanism may alsoinclude a lost motion connection between the connecting rod and ratchetgear drive mechanisms thereof in order to provide for infinite variationin the rotational movement of the ratchet gear, especially during theinitial phases of breaking loose an object to be rotated. The lostmotion connection effectively develops an impacting condition whichreadily accomplishes initial breaking loose of the object to be rotated.

With reference now to the drawings for a more detailed description of myinvention, in FIG. 1 I have illustrated a motor operated wrenchmechanism illustrated generally at which includes a wrench housing 12defined by a pair of opposed housing halves l4 and 16 maintained inassembly by a plurality of bolts 18. A rotary motor 20 is receivedwithin the housing 12 in such manner as to define a portion of thehandle structure of the motor operated wrench mechanism. The motor isillustrated in the drawings as an electric motor but it is quite obviousthat other rotary motor mechanisms such as pneumatic motors or internalcombustion engines may be employed within the spirit and scope of thisinvention. The motor structure 20 is provided with a handle 22 which isgrasped by personnel using the motor operated wrench mechansim. Anelectrical conductor 24 extends from a source of electrical energythrough the handle structure of the motor and is connected to theelectrical circuitry of the motor in conventional manner. Energizationof the motor 20 is controlled by means of a conventional electricalswitch, not shown, which is in turn controlled by a manually actuatedbutton 26. The motor 20 is provided with a rotatable shaft 28 which issupported intermediate its extremities by an antifriction bearing 30retained in a bearing aperture formed in the housing 32 of the motor.The bearing 30 is retained by a seal and bearing retainer 34 connectedto the motor housing 32 by means of screws 36. The motor housing 32 isprovided with a bearing support extension 38 in which is formed abearing aperture 40 having a bearing 41 therein receiving the freeextremity of the motor shaft 28. A worn gear 42 is disposed about therotatable motor shaft 28 and is maintained in non-rotatable relationwith the shaft 28 by a tapered pin 44extending through registeringapertures in the shaft 28 and worm gear.

A crank shaft 46 is supported by opposed antifriction bearings 48 and 50retained within bearing support bosses 52 and 54 defined internally ofthe housing halves 14 and 16 respectively. A worm wheel 56 is disposedin concentric non-rotatable relation with the crank shaft 46 and isdisposed in driving engagement with the worm gear 42 as illustrated inFIG. 1. The worm wheel 56 may be formed integrally with the crank shaft46 or may be connected in non-rotatable relation therewith in anydesired manner. As illustrated in FIGS. 1 and 2 of the drawings the wormwheel 56 is connected to the central portion 58 of the crank shaft 46 bymeans of a key 60 which is retained in registering keyways formed in theworm wheel and central portion of the crank shaft.

A pair of eccentric members 62 and 64 are formed integrally with thecrank shaft 46 about a common eccentrically located center and aredisposed within apertures formed in a pair of connecting rods 66 and 68respectively. Bearing members 70 and 72 are disposed within theconnecting rod apertures and provide bearing engagement with theeccentric members 62 and 64 respectively. The connecting rod 66 and 68are joined at one extremity thereof by means of screws 71 and areprovided with registering openings which cooperate to define anelongated aperture 73 retaining a connecting shaft 74. The connectingshaft 74 is secured to one of the connecting rods 68 by means of a setscrew 75.

As illustrated particularly in FIG. 3 the motor operated wrenchmechanism includes a ratchet gear 76 which is supported by upper andlower bearings 78 and 80 received within bearing apertures formed ininternal bosses 82 and 84 defined within the housing halves l4 and 16respectively.

A ratchet drive mechansim illustrated generally at 86 in FIG. 3 isprovided with upper and lower interfitting drive segments 88 and 90which are secured into assembly by means of a plurality of bolts 92. Aplurality of dowl pins 94 are received within registering blind boresformed in the upper and lower drive segments in order to add structuralintegrity to the ratchet drive assembly 86. The drive segments 88 and 90retain bearings 94 and 96 which define bearing apertures receiving theextremities of the connecting shaft 74. The ratchet drive assembly 86 isreceived in rotatable bearing engagement with exterior peripheralbearing surfaces forrned on bearing members 79 and 81 which are retainedon opposite sides of the ratchet gear 76. The ratchet drive assemblytherefore is freely rotatable within the housing 12 upon linear movementof the connecting rods 66 and 68.

A plurality of driving pawls 98 are pivotably connected to the ratchetdrive assembly 86 and are biased outwardly into engagement with theteeth 100 of the ratchet gear 76 by a plurality of compression springs102. A stop pawl 104 is pivotally retained within a boss 106 formedintegrally with and internally of the housing 12. A compression spring108 is retained within a spring recess formed in the housing and biasesthe stop pawl 104 into engagement with the teeth 100 of the ratchet gear76. The stop pawl is provided to prevent retrograde rotation of theratchet gear as the ratchet drive assembly 86 is being rotatedcounterclockwise as illustrated in FIG. 1 by the connecting rods 66 and68. As the ratchet drive assembly 86 rotates counterclockwise asillustrated in FIG. 1 the driving pawls 98 will advance the ratchet gear76 counterclockwise the distance of one or more ratchet teeth dependingupon the stroke of the connecting rods 66 and 68. As the ratchet driveassembly 86 is rotated clockwise the driving pawls 98 will be movedclockwise into engagement with other teeth of the ratchet gear 76 whilethe stopping pawl 104 prevents retrograde rotation of the ratchet gear.

The ratchet gear is provided with female splines 110 which receive themale spline 112 of a valve hand wheel adapter tool illustrated generallyat 114 in FIG. 5. The adapter tool 114 is provided with a ball springcatch 116 which locks the male splines 1 12 into driving engagement withthe female splines 110 of the ratchet gear. The adapter tool 114 is alsoprovided with a plurality of depending fingers or lugs 118 each beingprovided with a ball catch mechanism 120. The fingers or lugs 118 of theadapter tool 114 are received between the spokes 122 of a valve handwheel 124 in such manner that the ball spring catches engage the spokesin order to prevent inadvertant disassembly of the adapter tool from thehand wheel in the manner illustrated in FIG. 6.

With reference now to FIGS. 7 and 8 an alternate embodiment of my handwheel adapter tool is illustrated generally at 128 which includes a lugadjustment plate 130 having a shank 132 received within a centralaperture 134 formed therein. The shank 132 is provided with male splines136 which are received by the female splines 110 of the ratchet gear 76.The shank 136 may be welded or otherwise fixed to the plate 130 asindicated at 138 in order to achieve positive driving connection betweenthe shank 136 and the plate 130.

With reference particularly to FIG. 8 the plate 130 is provided with aplurality of radiating elongatedadjustment slots 140 in which arereceived adjustment bolts 142 having enlarged head portions 144including 0pposed flat surfaces 145 which cooperate with the walls ofthe slots 140 to prevent rotation of the bolts within the slots. Thebolts 142 are provided with upper flanges 146 which are larger than thewidth of the slots and which engage the upper surface of the plate 130.Hand wheel spoke engaging sleeves 148 are received about each of thebolts 142 and are maintainedin assembly with the bolts by a plurality ofnuts 150. The nuts 150 may be loosened and the bolts 142 along with thespoke engaging sleeves 148 may be adjusted radially within limitsdefined by the slots 140 to enable the hand wheel adapter tool 128 toreceive valve hand wheels of different size and configuration.

With reference now to FIG. 4, which illustrates a modified embodiment ofmy invention, a motor operated wrench mechanism, illustrated generallyat 152, includes a housing 154 of essentially identical configuration ascompared to the housing illustrated in FIGS. 1 through 3. A motor, notshown, is received by the housing 154 and is adapted to impart rotationto a worm gear 156 received by the motor shaft 158. A worm wheel 160 isdriven by the worm gear 156 and imparts rotation to upper and lowerintegral eccentric members l62'formed on a crank shaft 164 on eitherside of the worm wheel. A connecting rod 166 having a bifurcatedconnector portion 167 is maintained in assembly with the upper and lowereccentrics 162 by connecting rod caps 168 which are retained in assemblywith the upper and lower eccentric connector portion of the connectingrod by 'a plurality of bolts 170. A sleeve bearing 172 is interposedbetween the crank shaft and the eccentrics for the purpose of preventingwear of these parts.

A ratchet gear 174 is rotatably supported by upper and lower bearings176 which are retained by the housing halves in the same manner as thebearings 78 and 80 are retained by the housing halves 14 and 16respectively as illustrated in FIG. 3. The ratchet gear 174 is providedwith female splines 178 which receive the male splines of an adaptertool in driving engagement therewith.

A ratchet drive assembly, illustrated generally at 180 in FIG. 4, isrotatably retained within the housing 154 by bearing members inthe samemanner as the ratchet drive assembly 86 is rotatably supported-by theupper and lower bearings 79 and 81 as illustrated in FIG. 3. The ratchetdrive assembly 180 includes upper and lower drive segments which areretained in interfitting assembly and which cooperate to retain aplurality of driving pawls in pivotal relation therewith. The drivingpawls include a plurality of long pawls 182 and a plurality of shortpawls 184 which are biased into engagement with the teeth 186 of theratchet gear 174 by a plurality of compression springs 188. In the eventthe ratchet drive assembly 180 is rotated a distance of one or moreteeth in a counterclockwise direction before reversing the long drivepawls 182 upon reversing will be rotated clockwise into engagement withother teeth 186 of the ratchet gear 174. In the event the ratchet gear74 is not driven counterclockwise a distance of at least one tooth bythe ratchet drive assembly 180 upon counterclockwise rotation thereof,the short driving pawls 184 are capable of movement into drivingrelation with other ratchet gear teeth 186 upon partial clockwiserotation of the ratchet drive assembly. It is seen therefore that uponfull stroke rotation and counter rotation of the ratchet drive assemblythe long driving pawls 182 will drive the ratchet gear 174 and the shortdriving pawls 184 will not function. In the event however that rotationand counter rotation of the ratchet drive assembly is less than a fulltooth distance the short driving pawls 184 will provide the drivingfunction and the long driving pawls 182 will remain substantiallyinoperative. While two sets of long and short driving pawls areillustrated in FIG. 4 of the draw ings it is intended that other sets ofdriving pawls of varying length may be utilized within the spirit orscope of this invention to provide for less than full tooth drivingcapacity of the ratchet drive assembly.

A stop pawl 190 is pivotally supported by a boss 192 formed internallyof the housing 154. The stop pawl 190 is biased into engagement with theteeth 186 of the ratchet gear 174 by a compression spring 194 retainedwithin a spring recess in the boss 192. The stop pawl 190 is providedwith at least one step defining a second tooth engaging shoulder 196. Inthe event the ratchet gear 174 is rotated counterclockwise a distance ofat least one tooth the extreme end portion of the stop pawl '190 willengage a ratchet gear tooth to prevent retrograde rotation of theratchet gear when the ratchet drive assembly is reversed. In the eventthe ratchet gear 174 should be rotated counterclockwise a distance lessthan a full tooth the step or shoulder 196 of the stop pawl 190 willengage a ratchet gear tooth to prevent retrograde rotation of theratchet gear. In the event more than two sets of driving pawls areemployed it will be necessary to provide additional steps on the lockingpawl 190 to allow for partial tooth rotational control of the ratchetgear.

Each of the upper and lower segments of the ratchet drive assembly 180includes a driving arm 198 having a driving slot 200 formed therein. Theconnecting rod 166 includes a circular driving extremity 202 which isreceived within the driving slot 200 to provide a lost motion connectionbetween the connecting rod 166 and the ratchet drive assembly 180. Upperand lower tension springs 204 are retained between posts 206 on the arm198 and posts 208 on upper and lower extensions 210 of the connectingrod caps 168. The tension springs 204 bias the ratchet drive assembly inthe clockwise direction opposing the connecting rods 166 and maintainingthe extremity of the connecting rod in assembly with the driving recess200. i

In the event a valve hand wheel or the like should be very difficult toturn upon initial breakloose operation thereof the motor operated wrenchmechanism of this invention may be positioned relative to the hand wheelby relative angular adjustment of the motor operated wrench so that theratchet drive mechanism will be rotated counterclockwise almost to itsfully rotated position. The motor operated wrench mechanism will beenergized in this position causing the motor and worm gear drivemechanism to reciprocate the connecting rod 166 with the circularextremity 202 within the driving recess 200. Under this condition thecircular drive portion 202 of the connecting rod 166 will impact againstthe back portion of the slot 200 as the connecting rods reach the fullyextended position thereof. This impacting movement will induce smallincrements of rotation to the ratchet drive mechanism 180 in acounterclockwise direction causing the driving pawls 182 or 184 to drivethe ratchet gear 174. Under these conditions extremely high torqueforces are transmitted to the ratchet gear while only a minute rotationof the ratchet gear is achieved. A substantially frozen or extremelytight valve hand wheel may be broken loose in this manner and thennormal successive rotative movements may be imparted to the ratchet gear174 as counterclockwise movements of the ratchet drive mechanism becomeeasier. The lost motion connection also allows initial starting of themotor so that momentum of the motor can be achieved prior to placing aload on the driving structure of the wrench mechanism thereby promotinglong service free operating life of the wrench mechanism.

It will be evident from the foregoing that I have provided a novel motoroperated wrench mechanism which utilizes a rotary motor for impartingsuccessive rotative movements to an object to which the wrench mechanismis applied. The wrench mechanism includes a plurality of driving pawlswhich develop sufficient mechanical interconnection with a ratchet gearto prevent shearing of the teeth of the ratchet gear in the event amaximum load is applied by the ratchet gear drive mechanism. The ratchetgear drive mechanism is capable of achieving either full toothrotational stroke or partial tooth rotational stroke to achieve varyingincrements of rotation of the ratchet gear in order to achieve positiverotation of the object to be rotated regardless of the tightnessthereof. Further, my invention utilizes a lost motion connection betweenthe motor driven connecting rods and the ratchet drive assembly in orderto promote minute rotational control of the ratchet gear in the eventthe valve hand wheel or other object to be rotated may be substantiallyfrozen or extremely difficult to turn. The lost motion connection of myinvention also allows the electric or pneumatic drive motor to bebrought up to momentum before a driving load is placed thereon. Thisfeature effectively allows the use of motors which are of simple andreliable nature to drive the wrench mechanism. It is clearly apparentthat because of the simple and unique construction of my invention thatthe invention will be low in manufacturing cost and reliable in use. Itis obvious therefore that this invention effectively achieves all of thevarious objects noted hereinabove together with other advantages whichare obvious from a description of the apparatus itself.

I claim:

1. A motor operated wrench mechanism for imparting successive rotativemovements to an object to which said wrench mechanism is applied, saidwrench mechanism comprising a wrench housing, a rotary motor carried bysaid housing, a pair of eccentrics journaled for rotation within saidhousing, said motor imparting rotation to said eccentric connecting rodmeans being reciprocated by said motor means and being received by eachof said eccentrics, a ratchet drive mechanism journaled for rotatableoscillation within said wrench housing and including drive segmentsdefining a central opening, said connecting rod means engaging saidratchet drive mechanism and imparting oscillational movement thereto, aratchet gear journaled for rotation within said housing and beingreceived within said central opening, a plurality of driving pawlscarried by said ratchet gear, a locking pawl connected to said housingand engaging said ratchet gear to prevent retrograde rotation of saidratchet gear as said ratchet drive mechanism is oscillated, rotatabledrive means carried by said ratchet gear and being adapted to drivinglyengage the object to which the actuator mechanism is applied.

2. A motor driven actuator mechanism as set forth in claim 1, at leastone of said driving pawls engaging the teeth of said ratchet gear uponrotation of said ratchet gear less than a full successive movementstroke, said locking pawl having a partial stroke stop shoulder thereonand preventing retrograde rotation of said ratchet gear subsequent to apartial stroke rotational movement thereof.

3. A motor driven actuator mechanism as set forth in claim 1, a wormrotatably driven by said motor, a worm gear journaled for rotationwithin said housing and having said eccentrics formed thereon.

4. A motor driven actuator mechanism as set forth in claim 1, meansbiasing said ratchet drive mechanism in the retrograde rotativedirection, said connecting rod having a lost motion connection with saidratchet drive mechanism whereby the effective length of driving strokeof said connecting rod means may be varied by positioning said actuatormechanism rotatively relative to the object which is to be rotated toachieve slight successive rotational movements with extremely hightorque output of said actuator mechanism.

5. A motor operated wrench for imparting successive rotative movementsto an object to which the tool is applied, comprising a housing, a motorsupported by said housing, said motor having a rotatable shaft, a wormgear mounted on said shaft, a worm wheel having an eccentric crankshaftdefining an eccentric on either side of said worm gear, said worm wheelbeing operatively engaged by said worm gear, a ratchet drive assemblybeing journaled for rotation within said housing and defining a centralopening, a ratchet gear being journaled for rotation within said housingand being received within said central opening a connecting rod havingone end thereof engaging each of said eccentrics and the other endthereof being connected to said ratchet drive assembly, said ratchetgear having a female Spline formed therein, spring biased pawl meansengaging the ratchet gear to prevent reverse rotation of said gear, saidfemale spline being adpated to receive an adaptor tool having a splinedshank at one end adapted to fit in the female spline and with lugs atthe other end to fit over a hand wheel of a gate valve that is to beoperated upon.

1. A motor operated wrench mechanism for imparting successive rotativemovements to an object to which said wrench mechanism is applied, saidwrench mechanism comprising a wrench housing, a rotary motor carried bysaid housing, a pair of eccentrics journaled for rotation within saidhousing, said motor imparting rotation to said eccentric connecting rodmeans being reciprocated by said motor means and being received by eachof said eccentrics, a ratchet drive mechanism journaled for rotatableoscillation within said wrench housing and including drive segmentsdefining a central opening, said connecting rod means engaging saidratchet drive mechanism and imparting oscillational movement thereto, aratchet gear journaled for rotation within said housing and beingreceived within said central opening, a plurality of driving pawlscarried by said ratchet gear, a locking pawl connected to said housingand engaging said ratchet gear to prevent retrograde rotation of saidratchet gear as said ratchet drive mechanism is oscillated, rotatabledrive means carried by said ratchet gear and being adapted to drivinglyengage the object to which the actuator mechanism is applied.
 2. A motordriven actuator mechanism as set forth in claim 1, at least one of saiddriving pawls engaging the teeth of said ratchet gear upon rotation ofsaid ratchet gear less than a full successive movement stroke, saidlocking pawl having a partial stroke stop shoulder thereon andpreventing retrograde rotation of said ratchet gear subsequent to apartial stroke rotational movement thereof.
 3. A motor driven actuatormechanism as set forth in claim 1, a worm rotatably driven by saidmotor, a worm gear journaled for rotation within said housing and havingsaid eccentrics formed thereon.
 4. A motor driven actuator mechanism asset forth in claim 1, means biasing said ratchet drive mechanism in theretrograde rotative direction, said connecting rod having a lost motionconnection with said ratchet drive mechanism whereby the effectivelength of driving stroke of said connecting rod means may be varied bypositioning said actuator mechanism rotatively relative to the objectwhich is to be rotated to achieve slight successive rotational movementswith extremely high torque output of said actuator mechanism.
 5. A motoroperated wrench for imparting successive rotative movements to an objectto which the tool is applied, comprising a housing, a motor supported bysaid housing, said motor having a rotatable shaft, a worm gear mountedon said shaft, a worm wheel having an eccentric crankshaft defining aneccentric on either side of said worm gear, said worm wheel beingoperatively engaged by said worm gear, a ratchet drive assembly beingjournaled for rotation within said housing and defining a centralopening, a ratchet gear being journaled for rotation within said housingand being received within said central opening a connecting rod havingone end thereof engaging each of said eccentrics and the other endthereof being connected to said ratchet drive assembly, said ratchetgear having a female Spline formed therein, spring biased pawl meansengaging the ratchet gear to prevent reverse rotation of said gear, saidfemale spline being adpated to receive an adaptor tool having a splinedshank at one end adapted to fit in the female spline and with lugs atthe other end to fit over a hand wheel of a gate valve that is to beoperated upon.